Hide current working directory in Ubuntu Terminal

Just type below command in the Terminal.
export PS1='\u@\h:~$ '

Add above command to the bashrc file, so you do not have to type in the command again every time you load a new terminal.
sudo vi $HOME/.bashrc

Go to the bottom of the file and add the following using a editor such as VI.
export PS1='\u@\h:~$ '

Compile Hadoop Trunk on Ubuntu

Prerequisites

Install JDK
How to Install Oracle Java7 in Ubuntu Server 14.04 LTS

Install Maven
Install Maven on Ubuntu

Check if the ProtocolBuffers already installed?
protoc --version

Install ProtocolBuffers
sudo apt-get install protobuf-compiler  

Check the version
protoc --version

if the version does not display try following command.
sudo ldconfig
protoc --version

I have downloaded the "hadoop-trunk.zip" from Git Hub. 

if you want after the extract copy the  hadoop-trunk directory to your project working area.

sudo cp -r hadoop-trunk /home/mahesh/projects/hadoop/hadoop-trunk


Change the ownership of the hadoop-trunk direcoty to you. This should be done with '-R' (Recursive)
sudo chown -R mahesh hadoop-trunk

Compile  Hadoop
mvn install -DskipTests








If everything goes well you should see "BUILD SUCCESSFUL" message. Build would take a while to complete depending on you Internet connection speed, since Maven will download all the required artifacts in the first build.

 

mvn eclipse:eclipse -DdownloadSources=true -DdownloadJavadocs=true

'protoc --version' did not return a version

I came across this error while I was triying to Build Hadoop.

Check if the ProtocolBuffers already installed?
protoc --version

Install ProtocolBuffers
sudo apt-get install protobuf-compiler  

Check the version
protoc --version

if the version does not display try following command.
sudo ldconfig
protoc --version


The above steps should fix the issue. But while i was trying to figure out the issue I installed the following as well. 

apt-get -y install autoconf automake libtool cmake zlib1g-dev pkg-config libssl-dev

I got the above command from HowToContribute but i changed it.

apt-get -y install maven build-essential autoconf automake libtool cmake zlib1g-dev pkg-config libssl-dev

I removed the  "maven build-essential" from the command. since this will configure the Ubuntu with Open JDK and other tools which is not required.


Further Details can found in the following URI.
Trunk doesn't compile 

Install Maven on Ubuntu

Download and extract Maven.

Add Maven bin directory path to the bashrc file, so you can run Maven from any location. 
sudo vi $HOME/.bashrc

Go to the bottom of the file and add the following using a editor such as VI.
export M2_HOME=/usr/local/apache-maven-3.2.3
export PATH=$PATH:$M2_HOME/bin

Make sure JDK path is also set
export JDK_PREFIX=/usr/local/jdk1.7.0_71
export PATH=$PATH:$JDK_PREFIX/bin

ssh connect to host localhost port 22 connection refused ubuntu

Use the following command

sudo apt-get remove openssh-client openssh-server

More details Why am I getting a “port 22: Connection refused” error? 

Installing Apache Hardtop on Multi Node Fully Distributed Cluster

Create Virtual Machine Template
Build the initial VM by following the my blob post: Installing Apache Hadoop on a Single Node .
Follow the steps in the below Windows Azure article:
How to Capture a Linux Virtual Machine to Use as a Template


Create Five Node Cluster on Windows Azure
Virtual Machine 1 : Name Node and Job Tracker
Virtual Machine 2 : Secondary Name Node
Virtual Machine 3 : Data Node 1
Virtual Machine 4 : Data Node 2
Virtual Machine 5 : Data Node 3


Enable Localhost SSH
ssh-keygen -f "/home/mahesh/.ssh/known_hosts" -R localhost
Change the yellow highlighted text with your user name.

Copy SSH Key to each machine from the Name Node
ssh-copy-id -i $HOME/.ssh/id_rsa.pub mahesh@hd-name2
ssh-copy-id -i $HOME/.ssh/id_rsa.pub mahesh@hd-data1
ssh-copy-id -i $HOME/.ssh/id_rsa.pub mahesh@hd-data2
ssh-copy-id -i $HOME/.ssh/id_rsa.pub mahesh@hd-data3

If you get the error "/usr/bin/ssh-copy-id: ERROR: ssh: Could not resolve hostname hd-name2: Name or service not known". Change host name to the IP.

And if you happened to use the IP, change host namer of  "/usr/local/hadoop/conf/core-site.xml" and "/usr/local/hadoop/conf/mapred-site.xml" to IP of the Name Node.

Update "Masters" configuration file with Secondary Name node IP
sudo vi /usr/local//hadoop/conf/masters

Update "Slaves" configuration file with Data  node IPs (Each IP should be entered as a new line)
sudo vi /usr/local//hadoop/conf/slaves

Format the name node
hadoop namenode -format

Start Name, Secondary Name Node and Data Nodes
start-dfs.sh

Start Job Tracker and Task Trackers
start-mapred.sh

How to Install Oracle Java7 in Ubuntu Server 14.04 LTS

Add the webupd8team repository
sudo add-apt-repository ppa:webupd8team/java

Get package list 
sudo apt-get update

Download and Install the Oracle java 7
sudo apt-get install oracle-java7-installer

Verify the installation
java -version


Or else you can download the JDK from Oracle site. for example " dk-7u71-linux-x64.tar.gz"

Extract it the compressed JDK package

Add JDK bin directory path to the bashrc file, so you can run JDK from any location. 
sudo vi $HOME/.bashrc

export JDK_PREFIX=/usr/local/jdk1.7.0_71
export PATH=$PATH:$JDK_PREFIX/bin